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Aug 6, Charm 2007 1
γγ//φφ33 Impact from CLEO-c Using Impact from CLEO-c Using
CP-Tagged CP-Tagged D→KD→KS,LS,Lππππ Decays Decays
Eric White - University of IllinoisEric White - University of IllinoisQing He - University of RochesterQing He - University of Rochester
for the CLEO Collaborationfor the CLEO CollaborationCharm 07Charm 07
August 6, Charm 2007Eric White, University of Illinois 2
Path to Measuring Path to Measuring γγ//φφ33
B-
D0K-
D0K-
N ~ |fD|2 + rB2|fD|2 + 2|fD||fD|rB [cos(D)sin(B- ) – sin(D)cos(B- )]
Use B±→DK± decays, followed by Dalitz plot analysis of D→Ksπ+π -.
Developed by Giri, Grossman, Soffer, Zupan (GGSZ)[1] / Belle [2] -- exploit interference between D0 and D0 channels
(KSππ)K-
KSππ Dalitz Plot
favored path ~ VcbVus
suppressed path ~ VcsVub
fD
fD
Additional unknowns due to D0-D0 interference
5 parameters: rB, δB, γ, cos(D), sin(D) Measure at CLEO-c
Introduction Data KL-KS Binned Analysis Conclusion
[2] A.Bondar, Proceedings of Belle Special Analysis Meeting on Dalitz Analysis, 24-26 Sept. 2002, BINP, Novosibirsk (unpub.[1] Giri et al. Phys. Rev. D 68, 054018 (2003)
August 6, Charm 2007Eric White, University of Illinois 3
Current Current γγ//φφ33 Measurements Measurements
BaBar: 92o ± 41o(stat) ± 11o(syst) ± 12o(model)
(211 fb-1)
Belle: 53o ± 17o(stat) ± 3o(syst) ± 9o(model)
(357 fb-1)
10o model uncertainty will dominate → CLEO-c can help lower this number
Introduction Data KL-KS Binned Analysis Conclusion
Statistical uncertainty will go down to about ~ 6o with
projected 2 ab-1 (rB = 0.16)
(LHCb projects ~ 3o-5o uncertainty after 5 years… )
BaBar Collaboration, B. Aubert et al. hep-ex/0607104
Belle Collaboration, A. Poluektov et al. Phys. Rev. D73 (2006)
August 6, Charm 2007Eric White, University of Illinois 4
Measuring Measuring ccii with with CPCP-tagged -tagged KKSSππππ Dalitz Plots Dalitz Plots
Introduction Data KL-KS Binned Analysis Conclusion
M ~ |fD|2 + |fD|2 ± 2|fD||fD| cos(D)
For CP-tagged Dalitz plots, number of events in Dalitz plot is
Divide the (KS)D Dalitz plot in to bins, symmetric under interchange of π+ ↔ π – interchange.
Ψ(3770)
D DKS,LππCP Tag
Correlated DD pairs (C = -1) are produced at CLEO-cWe tag the KSππ sample by reconstructing D→CP± eigentstates
DCP± = D0 ± D0
√2
Define → ci = <cos(δD)>i
ci can be determined by
counting CP-tagged bins
i
-i
Binned Dalitz plot
CP-tagged flavor-tagged
August 6, Charm 2007Eric White, University of Illinois 5
Tagged Tagged KKSSππ++ππ –– Data from CLEO-c Data from CLEO-c
Event selection cuts
|ΔE| < 30 (MeV)
|KS mass| < 3σ
|Mbc - MD| < 4.2 (MeV)
(Mbc ≡ √((Ebeam)2 – (pD)2)
Very low background
We use 398 pb-1 of correlated Ψ(3770)→DD decaysFlavor-tagging modes: D0→K-π+, K-π+π0, K-π+π-π+ (plus charge-conjugate)
CP+ tags:
K+K-
π+π-
CP- tags:
KSπ0
KSη
Only two-body CP tags are used – provide clean signal with very little background
Flavor Tagged Data CP+ Tagged Data CP- Tagged Data
Mode
K+K-
π+π-
KSπ0
KSη
Yield
61
33
108
29
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 6
What about What about KKLLππππ??
Introduction Data KL-KS Binned Analysis Conclusion
Why not use KLππ?
Similar structure, opposite CP
More than doubles overall statistics
August 6, Charm 2007Eric White, University of Illinois 7
Tagged Tagged KKLLππ++ππ -- Data Data
Use same flavor and CP tag modes as KSππ, with same basic event selection
Mode
K+K-
π+π-
KSπ0
KSη
Yield
194
90
263
21Require additional π0, η veto
CP+ tags:
K+K-
π+π-
CP- tags:
KSπ0
KSη
Same two-body CP tags are used as KSππ:KLππ events are reconstructed
using “missing mass” technique
Flavor Tagged Data CP+ Tagged Data CP- Tagged Data
mK2 (GeV)2 mK
2 (GeV)2 mK2 (GeV)2
mK2 = 0.247
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 8
KKLLππ00 vs. vs. KKSSππππ
Similar event selection, with additional cuts: Require zero tracks 3σ cut on π0 mass Additional π0s vetoed
Reconstruct missing mass of KL
Doubles number of CP-even tags
Additionally, we use KLπ0 as CP-even tag for KSππ mode
This mode contains highest background level ~ 5%
Yield: 190 events
mK2 (GeV)2
KLπ0 Tagged Data
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 9
CP-tagged CP-tagged KKSSππ++ππ -- Dalitz Plots Dalitz Plots
KSρKSρ0 resonance enhanced
in CP-odd Dalitz plot
CP-odd KSρ0 resonance absent
in CP-even Dalitz plot
Introduction Data KL-KS Binned Analysis Conclusion
M2(KSπ+)
August 6, Charm 2007Eric White, University of Illinois 10
CP-tagged CP-tagged KKLLππ++ππ -- Dalitz Plots Dalitz Plots
KLρ
Since CP of KL is opposite to KS,
KLππ Dalitz plot contains opposite
CP structure to that of KSππ
KLρ0 resonance enhanced
in CP-even Dalitz plot
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 11
Flavor-tagged Flavor-tagged KKS,LS,Lππ++ππ -- Dalitz Plots Dalitz Plots
There is a clear difference in the
DCS K*+ peak
Appears constructively in KLππ,
and destructively in KSππ
The KS,Lππ Dalitz plots are not
exactly equal
Must take this into account before combining ci measurements for KLππ and KSππ samples
M2(KSπ+)
M2 (
KSπ- )
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 12
Combining Combining ccii from from K KSSππππ and and KKLLππππ
Introduction Data KL-KS Binned Analysis Conclusion
KS and KL can be expressed: CF DCS
A(D0→KSππ) = K*-(CF) + K*+(DCS) + f0 + ρ0 + …
A(D0→KLππ) = K*-(CF) - K*+(DCS) + (1-2rei?)f0 + (1-2rei?)ρ0 + …
Define r as the
magnitude of
DCS/CF ratio
r is small (~ 0.06), but
is the phase known?
By varying each unknown phase and recalculating ci ,
we can determine a measure of the systematic uncertainty for KLππ
Value of ci is in general different for KLππ and KSππ,
but can be related through U-spin symmetry
August 6, Charm 2007Eric White, University of Illinois 13
Binned AnalysisBinned Analysis
si can be determined from ci → si = ±√1 – ci2
Provided fluctuations of phase difference δD
across bins are small
Variation of δD phase can be minimized by choosing
a more intelligent, model-inspired binning:
We use N = 8 bins
in this analysisΔδD = 0ΔδD = π
m+2
m-2
Belle Collaboration, A. Poluektov et al. Phys. Rev. D73, 112009 (2006)Bondar, Poluektov hep-ph/0703267v1 (2007)
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 14
Comparing Comparing ccii for for KKS,LS,Lππ++ππ --
Obtain KLππ model by changing sign of DCS terms → K*+(892), K*+(1410)…
Calculate ci from KSππ and KLππ models
Vary phase for each resonance, keep largest difference in ci
KSππKLππ
ci calculated from model
ci difference
model
398 pb-1 Systematic uncertainty from KLππ is
small compared to ci difference
Good agreement of ci difference in data
Introduction Data KL-KS Binned Analysis Conclusion
August 6, Charm 2007Eric White, University of Illinois 15
Sensitivity to Sensitivity to ccii
We combine KLππ, KSππ Dalitz plots into an improved overall measurement of ci
Scale statistical uncertainty up to full 750 pb-1
Combine with KLππ systematic uncertainty to determine overall expected sensitivity from
CLEO-c measurement
Introduction Data KL-KS Binned Analysis Conclusion
ci calculated from model
Error bars represent
expected uncertainty,
as projected from current
data sample
August 6, Charm 2007Eric White, University of Illinois 16
ConclusionConclusion
Introduction Data KL-KS Binned Analysis Conclusion
KLππ, KSππ samples can be combined
Good sensitivity to ci
Total DCP expected to be ~ 1,530 for 750 pb-1
Combined BaBar/Belle (2 ab-1) statistical uncertainty → ±6o
CLEO-c can reduce model uncertainty from ±10o down to ± 4o in γ/φ3 measurement
August 6, Charm 2007Eric White, University of Illinois 17
Back upBack up
Following modes will also be used to measure ci and si
KSππ vs. KSππ (~ 480)
KSππ vs. KLππ (~ 1240)} Expected yields (750 pb-1)
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